Every forum has its own setting for "Can download attachments", you'll need to set it so the users group can download images/attachments in every forum.
Attachments
Screenshot_2020-07-11 Forum - UBB threads PHP Forum Software Community Control Panel.png

I am a Web Development Contractor, I do not work for UBBCentral. I have provided free User to User Support since the beginning of these support forums.
Do you need Forum Install or Upgrade Services?
Forums: A Gardeners Forum
UBB.threads: UBBWiki, UBB Styles, UBB.Sitemaps
Longtime Supporter & Resident Post-A-Holic
VNC Web Services: Code Modifications, Upgrades, Styling, Coding Services, Disaster Recovery, and more!